4-1/2", carbon steel, knotted wire wheel, x-lock arbor, stringer bead, design offers faster, fixed mount & high-quality materials, snap-on wheel mounting & release lever for change-out that's up to 5x faster, wheel mounts properly without the need for a spanner wrench or flange nuts, no easy to lose parts, features extremely narrow tufted faces for confined areas such as cross-country pipelines & pipe fabrication, as well as brushing expansion joints & narrow grooves, robust applications for metal designed to be ideal for deburring metal, bead weld prep, cleaning welds & edge blending, precision-balanced wheel virtually eliminates vibration, application focused designed specifically for use with x-lock small angle grinder.